Dynamic control of surgical instruments in a surgical robotic system using repulsion/attraction modes

ABSTRACT

A robot-assisted surgical system has a user interface operable by a user, a first robotic manipulator having a first surgical instrument, and a second robotic manipulator having a second surgical instrument. The system receives user input in response to movement of the input device by a user and causes the manipulator to move the first surgical instrument in response to the user input, determines a vector defined by the position of the first surgical instrument relative to the second surgical instrument, generates dynamic control signals based on the determined vector, and causes the manipulator to move the second surgical instrument in response to said dynamic control signals.

This application is a continuation of U.S. application Ser. No.16/733,154, filed Jan. 2, 2020, now U.S. patent Ser. No. 11/607,283,which claims the benefit of U.S. Provisional Application No. 62/787,339,filed Jan. 1, 2019.

BACKGROUND

There are various types of surgical robotic systems on the market orunder development. Some surgical robotic systems use a plurality ofrobotic arms. Each arm carries a surgical instrument, or the camera usedto capture images from within the body for display on a monitor. Othersurgical robotic systems use a single arm that carries a plurality ofinstruments and a camera that extend into the body via a singleincision. Each of these types of robotic systems uses motors to positionand/or orient the camera and instruments and to, where applicable,actuate the instruments. Typical configurations allow two or threeinstruments and the camera to be supported and manipulated by thesystem. Input to the system is generated based on input from a surgeonpositioned at a master console, typically using input devices such asinput handles and a foot pedal. Motion and actuation of the surgicalinstruments and the camera is controlled based on the user input. Theimage captured by the camera is shown on a display at the surgeonconsole. The console may be located patient-side, within the sterilefield, or outside of the sterile field.

The Senhance Surgical System marketed by Asensus Surgical, Inc.(formerly TransEnterix, Inc.) is a robotic system allowing surgeoncontrol of the robotic manipulator that supports the camera by allowingthe surgeon to control the camera using an eye tracking system. Theother two or three robotic manipulators carrying surgical instrumentsare driven via handles in a surgeon console. Since the surgeon has justtwo hands, operation of the system in procedures utilizing more than twosurgical instruments on robotic manipulators requires the surgeon tochoose which two instruments s/he will control using the console at anygiven moment.

In a laparoscopic surgical procedure performed using three manualinstruments and a camera, the surgeon manipulates the two primaryinstruments with his/her right and left hands while a surgical assistantcontrols the camera and third instrument. Robotic surgery thus gives thesurgeon increased control relative to traditional laparoscopy by givinghim/her direct control over the camera and third instrument rather thanrequiring reliance on another person to move those instruments. However,this control lacks the dynamic element of control that occurs in manuallaparoscopic procedures where, for example, the surgical assistant movesthe camera or third instruments in response to movement of the otherinstruments or in anticipation of what will next occur with thoseinstruments. Instead, the surgeon must associate the third instrumentwith a handle of the user input to initiate movement of that instrumentor give the system some additional input to cause movement of the cameraor third instrument.

This application describes certain modes of operation that enabledynamic, surgeon-controlled movement of a third instrument while thesurgeon also controls the two primary instruments.

Although the inventions described herein may be used on a variety ofrobotic surgical systems, the embodiments will be described withreference to a system of the type shown in FIG. 1 . In the illustratedsystem, a surgeon console 12 has two input devices such as handles 17,18 that the surgeon selectively assigns to two of the roboticmanipulators 14, 15, 16, allowing surgeon control of two of the surgicalinstruments 10 a, 10 b, and 10 c disposed at the working site at anygiven time. To control a third one of the instruments disposed at theworking site, one of the two handles 17, 18 is operatively disengagedfrom one of the initial two instruments and then operatively paired withthe third instrument. A fourth robotic manipulator, not shown in FIG. 1, supports and maneuvers the laparoscopic camera. The camera may be usedby the fourth robotic manipulator using input from an eye tracker 21disposed at the surgeon console 12.

A control unit 30 is operationally connected to the robotic arms and tothe user interface. The control unit receives user input from the inputdevices corresponding to the desired movement of the surgicalinstruments, and the robotic arms 14, 15 and 16 are caused to manipulatethe surgical instruments accordingly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates elements of a surgical robotic systemof a type that may be adapted for use with the disclosed invention.

FIG. 2 schematically illustrates the distal ends of two surgicalinstruments within an operative field with the use ofrobotically-controlled “repulsion” of one the instruments with respectto the other instrument;

FIG. 3 schematically illustrates the distal ends of two surgicalinstruments within an operative field with the use ofrobotically-controlled “attraction” of one the instruments with respectto the other instrument;

DETAILED DESCRIPTION

The purpose of this disclosure is to describe a mode of operation thatenables dynamic, system-controlled movement of a fourth roboticmanipulator (third instrument, it being assumed that the thirdmanipulator is used to move the camera) while the surgeon controls themovement and operation of the robotic manipulators carrying the twoprimary instruments. The surgical system may be of a type described inthe Background, or any other type of robotic system used to maneuversurgical instruments at an operative site within the body. In someembodiments, the surgical system is one that includes sensors positionedto estimate the forces imparted against each robotically manipulatedsurgical instrument by tissue or other instruments.

In this description, the terms “primary instruments” or “primary controlinstruments” will refer to the surgical instruments moveable by roboticmanipulators in accordance with the input delivered to the system by thesurgeon inputs at the surgeon console. Typically, the surgicalinstruments under direct control of the user inputs at the surgeonconsole are the primary instruments. In a practical sense these are theinstruments on robotic manipulators that are assigned to correspondinguser input devices. Assignment can include assignment using affirmativeinstrument pairing input by a user, using an eye tracker or alternateinput device, or more automated assignment in accordance with analgorithm (e.g. an instrument detection/recognition algorithm resultingin automatic assignment of robotic manipulators to user input devicesbased on where their corresponding instruments are “seen” by theendoscopic camera in the image view). Primary control instruments may beinstruments that move in accordance with the direction, velocity orparameter (or a scaled version of each, according to the scaling factorsin use for their operation), or to the location in the body, at/to whichthe surgeon has deliberately and directly directed them to move usingthe user input device. Thus primary control instruments include thoseoperatively associated with the user input so they move in the directionand at the rate (or scaled version of either) at which the surgeon isdirecting them to move using the user input device, even if the systemimposes limits on instrument movement such as dynamic rate-slowing astargets are approached, velocity limits, no-fly-zone limits etc.

The term “secondary instrument,” “secondary control instrument,” or“third instrument” or “dynamically controlled instrument” will refer toan instrument that is also moveable by a robotic manipulator, but whosemovement characteristics (e.g. direction, orientation) is based in someway on the characteristics of the directed movement of the one of theprimary instruments. In a practical sense this type of instrument is oneon a robotic manipulator that has not been uniquely assigned to orpaired with a corresponding user input device. While it will be typicalfor two primary instruments to be used, in some embodiments there mightjust be one primary instrument. For example, there might just be oneprimary instrument in a configuration where only one instrument is beingcontrolled by a user input handle because the other user input handle iscontrolling the camera.

The primary embodiment in this disclosure is a mode of operation where aset of governing laws controls the movement of a third instrument. Thismode may be referred to as “Magnet” mode or attraction/repulsion modebecause there are times where the third instrument needs to move towardsas the two primary instruments and other times where it should move awayfrom the primary instruments. In an attraction mode the dynamicallycontrolled instrument is caused to move, with respect to the primarycontrol instrument, as if it is being magnetically attracted to theprimary control instrument. In a repulsion mode the dynamicallycontrolled instrument is caused to move, with respect to the primarycontrol instrument, as if it is being magnetically repulsed by theprimary control instrument.

In a “magnet” mode, the third instrument is dynamically controlled sothat it will “repulse” away from the primary instruments, as depicted inFIG. 2 , when the primary instruments get within a certain distance ofone another and such that it will “attract” towards the primaryinstrument, as depicted in FIG. 3 , when the primary instruments arebeyond a certain distance. The repulsion or attraction will be acombination of force and position, meaning the vector between the tworepulsing or attracting instruments will dictate the amplitude anddirection of the applied force to the dynamically controlled instrument.This applied force will be constrained so that it does not put excessforce onto tissue and the maximum instrument displacement will beconstrained. Maximum displacement may be characterized as the maximumdisplacement from a first position to a second position, or as thedisplacement from the primary instrument in a given direction or in anydirections. These constraints can prevent movement of the instrumentinto an area the surgeon does not wish the instrument to enter orunintended collisions with other instruments or tissues.

FIG. 2 schematically illustrates a mode of operation in which thesecondary instrument behaves as if there are repulsive forces betweenthe instruments. As an example of repulsion, in cholecystectomy, thethird instrument is holding the fundus of the gallbladder during theoperation. While the primary instruments are working to remove thegallbladder from the liver bed, the primary instruments are slowlyworking towards the fundus. As the primary instruments get closer andcloser to the fundus, the force applied to the fundus by the thirdinstrument is increased, lifting the gallbladder further. Protectionswould be in place to stop movement if force or position limits arereached, or when the gallbladder has been completely removed from theliver bed. These events may be detected using input from the systemsforce/torque sensor, which, in the case of complete separation of thegallbladder, while rapidly decrease.

Additionally, the third instrument would exhibit attraction to theprimary instruments when the vector to the primary instruments is beyonda defined threshold. This may be helpful in keeping the instrumentswithin view of the laparoscope or for dynamically controlling theretraction of tissue while in tight spaces. For example, a thirdinstrument shaft could be used to hold up bowel or liver during aprocedure. As the primary instruments get closer, the third instrumentwould repulse away, clearing more space. However, as the primaryinstruments move away from the third instrument, the third instrumentcould follow, reducing the tissue retraction and making it easier tofind/move to a new desired location, later in the case. FIG. 3schematically illustrates the mode of operation in which the secondaryand, optionally, the primary instrument behaves as if there areattractive forces between them.

Thus, the third instrument could find itself in one of three states: (1)Too close to another instrument and repulsing away (2) Too far away froman instrument and attracting closer or (3) In a goldilocks zone where itis neither too close or too far, so it simply maintains position/force.

The rules governing the repulsion and attraction of the third instrumentcould be pre-defined and unique to each surgical intervention. The rulescould also be adjusted through the surgeon interface. Additionally,surgeon control of the third instrument would still be possible throughassigning it to one of the surgeon console handles or through switchingto other modes of operations, as described in other disclosures.

The disclosed system thus provides mode of operation that enables thesystem to control the movement of an instrument that is not under thedirect control a user input device, within pre-defined, operativelimits. These modes of operation provide a number of advantages, whichinclude:

-   -   dynamic control over the “third” (unassigned) in a robotic        surgical system    -   enabling the system to provide dynamic movement of the third        instrument while the surgeon maintains control over the primary        instruments.

We claim:
 1. A method of performing surgery with a surgical roboticsystem, comprising: positioning a first surgical instrument on a firstrobotic manipulator and positioning a second surgical instrument on asecond robotic manipulator; positioning a distal part of the firstsurgical instrument in a patient body cavity, and positioning a distalpart of the second surgical instrument in a patient body cavity;operatively assigning the first robotic manipulator to a user interfacefor movement of the first surgical instrument in response to user inputsignals generated from a user control at the user interface; generatingdynamic control signals based on a vector defined by the position of thefirst surgical instrument relative to the second surgical instrument,wherein the second robotic manipulators is moveable in response to saiddynamic control signals to move the second surgical instrument.
 2. Themethod of claim 1 where the dynamic control signals cause movement ofthe second surgical instrument based on a vector defined by the positionof the first surgical instrument relative to the second surgicalinstrument.
 3. The method of claim 2, where the dynamic control signalscause movement of the second surgical instrument away from the firstsurgical instrument when a distance between the first surgicalinstrument and the second surgical instrument falls below a predefineddistance, thereby increasing the distance between the first surgicalinstrument and the second surgical instrument.
 4. The method of claim 3,wherein the dynamic control signals cause the second robotic manipulatorto apply a repulsive force to the second surgical instrument, whereinthe repulsive force dynamically adjusts depending on the distancebetween the first surgical instrument and the second surgicalinstrument.
 5. The method of claim 3, further including limiting theforce and position of the second surgical instrument resulting from thedynamic control signals to within predefined or dynamic boundaries. 6.The method of claim 2, where the dynamic control signals cause movementof the second surgical instrument towards the first surgical instrumentwhen a distance between the first surgical instrument and the secondsurgical instrument exceeds a predefined distance, thereby decreasingthe distance between the first surgical instrument and the secondsurgical instrument.
 7. The method of claim 6, wherein the dynamiccontrol signals cause the second robotic manipulator to apply anattractive force to the second surgical instrument, wherein theattractive force dynamically adjusts depending on the distance betweenthe first surgical instrument and the second surgical instrument.
 8. Themethod of claim 6, wherein the method limits the force and position ofthe second surgical instrument resulting from the dynamic controlsignals to within predefined or dynamic boundaries.
 9. A robot-assistedsurgical method comprising: providing a user interface operable by auser, a first robotic manipulator having a first surgical instrument,and a second robotic manipulator having a second surgical instrument;receiving user input in response to movement of the user interface by auser and cause the manipulator to move the first surgical instrument inresponse to the user input; determining a vector defined by the positionof the first surgical instrument relative to the second surgicalinstrument, generating dynamic control signals based on the determinedvector, and causing the second robotic manipulator to move the secondsurgical instrument in response to said dynamic control signals.
 10. Themethod of claim 9, where the dynamic control signals cause movement ofthe second surgical instrument away from the first surgical instrumentwhen a distance between the first surgical instrument and the secondsurgical instrument falls below a predefined distance, therebyincreasing the distance between the first surgical instrument and thesecond surgical instrument.
 11. The method of claim 10, wherein thedynamic control signals cause the second robotic manipulator to apply arepulsive force to the second surgical instrument, wherein the repulsiveforce dynamically adjusts depending on the distance between the firstsurgical instrument and the second surgical instrument.
 12. The methodof claim 11, further including limiting the force and position of thesecond surgical instrument resulting from the dynamic control signals towithin predefined or dynamic boundaries.
 13. The method of claim 9,where the dynamic control signals cause movement of the second surgicalinstrument towards the first surgical instrument when a distance betweenthe first surgical instrument and the second surgical instrument exceedsa predefined distance, thereby decreasing the distance between the firstsurgical instrument and the second surgical instrument.
 14. The methodof claim 13, wherein the dynamic control signals cause the secondrobotic manipulator to apply an attractive force to the second surgicalinstrument, wherein the attractive force dynamically adjusts dependingon the distance between the first surgical instrument and the secondsurgical instrument.
 15. The method of claim 13, further includinglimiting the force and position of the second surgical instrumentresulting from the dynamic control signals to within predefined ordynamic boundaries.